A broadband ±45° dual-polarized millimeter wave subarray and phased array antenna

Abstract

The application discloses a broadband ±45° dual-polarized millimeter wave subarray and phased array antenna, comprising first dielectric substrate, first metal plate, second dielectric substrate, second metal plate, third dielectric substrate and third metal ground plate arranged in sequence; the first dielectric substrate is provided with a plurality of ±45° dual-polarized antenna units arranged in array and a plurality of decoupling ground branches, the first metal plate is etched with a plurality of cross-shaped feed slots, the second dielectric substrate is provided with a-45° feed network, the second metal plate is etched with a plurality of third I-shaped slots, and the third dielectric substrate is provided with a +45° feed network; the ±45° dual-polarized antenna units, the cross-shaped feed slots and the third I-shaped slots are arranged one by one and correspond to each other; the decoupling ground branch can effectively improve the isolation of the ±45° dual-polarized subarray and avoid affecting port matching.

Description

Technical Field

[0001] This invention belongs to the field of millimeter-wave communication technology, specifically relating to a broadband ±45° dual-polarized millimeter-wave subarray and phased array antenna. Background Technology

[0002] With the rapid development of information technology, fifth-generation mobile communication (5G) has become a global hot topic, and ultra-wideband, low latency, and high speed have become new requirements for communication technology. Wideband ±45° dual-polarized millimeter-wave phased arrays, as one of the requirements of 5G millimeter-wave communication, have become a research hotspot in recent years. However, the technology of wideband ±45° dual-polarized millimeter-wave phased arrays is still immature. Typical problems include: (1) severe coupling between ±45° polarizations, which affects antenna efficiency; (2) narrow beam scanning range and deterioration of cross-polarization during wide-angle scanning. This has greatly restricted the application of this technology in 5G. In order to improve the coupling between ±45° polarizations, the traditional method is to use dielectric loading. However, this decoupling method will bring many problems such as additional profiles, complex design, and high processing difficulty, which poses a great challenge to the overall design of the antenna array. Therefore, it is of great significance to design a wideband ±45° dual-polarized millimeter-wave phased array antenna that is easy to process, highly isolated, and has good scanning function. Summary of the Invention

[0003] The purpose of this invention is to provide a broadband ±45° dual-polarized millimeter-wave subarray and phased array antenna, which can effectively improve the isolation of the ±45° dual-polarized subarray while avoiding the impact on port matching.

[0004] The first aspect of the present invention provides a broadband ±45° dual-polarized millimeter-wave subarray, comprising a first dielectric substrate, a first metal plate, a second dielectric substrate, a second metal plate, a third dielectric substrate, and a third metal ground plane arranged in sequence.

[0005] The first dielectric substrate is arranged in an array of several ±45° dual-polarized antenna elements and several decoupling grounding branches. The first metal plate is etched with several cross-shaped feed slots. The second dielectric substrate is provided with a -45° feed network and the second metal plate is etched with several third I-shaped slots. The third dielectric substrate is provided with a +45° feed network. The ±45° dual-polarized antenna elements, cross-shaped feed slots and third I-shaped slots are arranged in a corresponding manner to each other.

[0006] The decoupling grounding stub is set between every two ±45° dual-polarized antenna elements. The decoupling grounding stub acts to change the coupling amplitude and phase of the ±45° polarization between the ±45° dual-polarized antenna elements, so that the ±45° polarization coupling cancels each other out.

[0007] Preferably, the decoupling grounding branch includes two first metal strips placed side by side and two second metal strips placed side by side; the second metal strips are disposed between the two first metal strips, and the first metal strips and the second metal strips are arranged perpendicular to each other; a first grounding post is provided at the center of the first metal strip; the first grounding post is embedded in the first dielectric substrate; the first grounding post is connected to the first metal plate.

[0008] Preferably, the first metal strip and the second metal strip are configured as π-shaped, n-shaped, H-shaped, L-shaped, M-shaped or T-shaped; the first grounding post is a cuboid or a cylinder.

[0009] Preferably, the cross-shaped gap includes a first I-beam gap and a second I-beam gap arranged perpendicularly to each other, the first I-beam gap and the second I-beam gap respectively acting to excite -45° polarization and +45° polarization.

[0010] Preferably, the -45° power supply network and the +45° power supply network include a power divider and a metal isolation strip; the metal isolation strip is arranged around the power divider; and second grounding posts are evenly distributed on the metal isolation strip.

[0011] Preferably, the first dielectric substrate, the second dielectric substrate, and the third dielectric substrate are low-temperature co-fired ceramic substrates or PCB dielectric substrates.

[0012] Preferably, the ±45° dual-polarized antenna unit includes four triangular metal patches; the triangular metal patches are arranged in an array around the center of the ±45° dual-polarized antenna unit; a third grounding post is provided on each triangular metal patch near the center of the ±45° dual-polarized antenna unit; the second grounding post is connected to the first metal plate.

[0013] The first aspect of the present invention provides a phased array antenna, characterized in that it includes a plurality of highly isolated broadband ±45° dual-polarized millimeter-wave subarrays arranged in an array; cross-polarization is suppressed when scanning to the maximum angle by loading decoupling ground stubs, while making gain fluctuations more stable.

[0014] Compared with the prior art, the beneficial effects achieved by the present invention are as follows:

[0015] In this invention, the first dielectric substrate is arranged in an array of several ±45° dual-polarized antenna elements and several decoupling grounding stubs. The first metal plate is etched with several cross-shaped feed slots. The second dielectric substrate is provided with a -45° feed network and the second metal plate is etched with several first I-shaped slots. The third dielectric substrate is provided with a +45° feed network. The ±45° dual-polarized antenna elements, cross-shaped feed slots, and first I-shaped slots are arranged in a one-to-one correspondence. The decoupling grounding stubs used are also suitable for broadband, which can effectively improve the isolation of the ±45° dual-polarized subarray, avoid affecting port matching, and also effectively improve the scanning performance of the ±45° dual-polarized phased array, suppress cross-polarization during large-angle scanning, and effectively improve the scanning performance of the phased array antenna, making the gain fluctuation more stable during scanning. Attached Figure Description

[0016] Figure 1 This is a three-dimensional schematic diagram of the structure of the broadband ±45° dual-polarized millimeter-wave subarray in Embodiment 1 of the present invention;

[0017] Figure 2 This is a top view of the broadband ±45° dual-polarized millimeter-wave subarray in Embodiment 1 of the present invention;

[0018] Figure 3 This is a side view of the broadband ±45° dual-polarized millimeter-wave subarray in Embodiment 1 of the present invention;

[0019] Figure 4 This is a top view of the first metal plate of the broadband ±45° dual-polarized millimeter-wave subarray in Embodiment 1 of the present invention;

[0020] Figure 5 This is a top view of the second metal plate of the broadband ±45° dual-polarized millimeter-wave subarray in Embodiment 1 of the present invention;

[0021] Figure 6 This is a top view of the second dielectric substrate of the broadband ±45° dual-polarized millimeter-wave subarray in Embodiment 1 of the present invention;

[0022] Figure 7 This is a top view of the third dielectric substrate of the broadband ±45° dual-polarized millimeter-wave subarray in Embodiment 1 of the present invention;

[0023] Figure 8 This is the S-parameter curve of the broadband ±45° dual-polarized millimeter-wave subarray before the decoupling grounding stub was loaded in Embodiment 1 of the present invention;

[0024] Figure 9 This is the S-parameter curve of the broadband ±45° dual-polarized millimeter-wave subarray after loading decoupling grounding stubs in Embodiment 1 of the present invention;

[0025] Figure 10This is the antenna efficiency curve before and after loading the decoupling grounding stub into the broadband ±45° dual-polarized millimeter-wave subarray in Embodiment 1 of the present invention;

[0026] Figure 11 This is a three-dimensional schematic diagram of the phased array antenna structure in Embodiment 2 of the present invention;

[0027] Figure 12 This is a top view of the phased array antenna in Embodiment 2 of the present invention;

[0028] Figure 13 These are the reflection coefficient curves of each port of the phased array antenna in Embodiment 2 of the present invention.

[0029] Figure 14 This is the coupling coefficient curve between the ±45° polarizations of each subarray of the phased array antenna in Embodiment 2 of the present invention.

[0030] Figure 15 This refers to the main polarization and cross polarization of the phased array antenna in Embodiment 2 of the present invention when it is scanned to the maximum angle before and after loading the decoupling grounding stub;

[0031] Figure 16 This is a comparison chart of the scanning performance of the phased array antenna in Embodiment 2 of the present invention before and after loading a decoupling grounding stub;

[0032] Figure 17 This is the scanning performance diagram of the phased array antenna in Embodiment 2 of the present invention at 24.25 GHz when it is individually excited to -45° polarization;

[0033] Figure 18 This is a scanning performance diagram of the phased array antenna in Embodiment 2 of the present invention at 27 GHz when it is individually excited to -45° polarization;

[0034] Figure 19 This is a scanning performance diagram of the phased array antenna in Embodiment 2 of the present invention at 29.5 GHz when it is individually excited to -45° polarization.

[0035] Figure 20 This is the scanning performance diagram of the phased array antenna in Embodiment 2 of the present invention at 24.25 GHz when it is individually excited with +45° polarization;

[0036] Figure 21 This is the scanning performance diagram of the phased array antenna in Embodiment 2 of the present invention at 27 GHz when it is individually excited and polarized at +45°.

[0037] Figure 22 This is the scanning performance diagram of the phased array antenna in Embodiment 2 of the present invention at 29.5 GHz when it is individually excited and polarized at +45°.

[0038] Figure 23These are the active S-parameters of the phased array antenna in Embodiment 2 of the present invention when it is scanned to the maximum angle under -45° polarization alone.

[0039] Figure 24 These are the active S-parameters of the phased array antenna in Embodiment 2 of the present invention when it is scanned to the maximum angle under +45° polarization alone.

[0040] In the figure: 1 First dielectric substrate, 2 First metal plate, 3 Second dielectric substrate, 4 Second metal plate, 5 Third dielectric substrate, 6 Third metal ground plane, 7 ±45 degree dual-polarized antenna element, 8 Decoupling grounding stub, 9 First metal strip, 10 Second metal strip, 11 First grounding post, 12 Cross-shaped feed slot, 13 First H-shaped slot, 14 Second H-shaped slot, 15 Third H-shaped slot, 16 -45° feed network, 17 Power divider, 18 Metal isolation strip, 19 Second grounding post, 20 +45° feed network, 21 Triangular metal patch, 22 Third grounding post. Detailed Implementation

[0041] The present invention will be further described below with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and should not be used to limit the scope of protection of the present invention.

[0042] It should be noted that in the description of this invention, the terms "front," "rear," "left," "right," "upper," "lower," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These terms are used only for the convenience of describing the invention and do not require the invention to be constructed and operated in a specific orientation; therefore, they should not be construed as limitations on the invention. The terms "front," "rear," "left," "right," "upper," and "lower" used in the description of this invention refer to the directions shown in the accompanying drawings, while the terms "inner" and "outer" refer to directions toward or away from the geometric center of a specific component, respectively.

[0043] Example 1

[0044] like Figures 1 to 10 As shown, a broadband ±45° dual-polarized millimeter-wave subarray and phased array antenna includes a first dielectric substrate 1, a first metal plate 2, a second dielectric substrate 3, a second metal plate 4, a third dielectric substrate 5, and a third metal ground plate 6 stacked sequentially; it adopts a multilayer LTCC process; the first dielectric substrate 1, the second dielectric substrate 3, and the third dielectric substrate 5 are made of FerroA6M dielectric substrate.

[0045] The first dielectric substrate 1 is arranged in an array of several ±45° dual-polarized antenna elements 7 and several decoupling grounding stubs 8. Each decoupling grounding stub 8 includes two first metal strips 9 placed side by side and two second metal strips 10 placed side by side. The second metal strips 10 are disposed between the two first metal strips 9 and are connected to the first metal strips 9. The first metal strips 9 and the second metal strips 10 are arranged perpendicular to each other. A first grounding post 11 is provided at the center of the first metal strip 9. The first grounding post 11 is embedded in the first dielectric substrate 1 and is connected to the first metal plate 2.

[0046] The decoupling grounding stub 8 is disposed between every two ±45° dual-polarized antenna elements 7. The decoupling grounding stub 8 acts to change the coupling amplitude and phase between the ±45° polarizations of the elements, so that they cancel each other out, thereby improving the isolation between the ±45° polarizations of the subarray. The first metal strip 9 and the second metal strip 10 are configured as π-shaped, n-shaped, H-shaped, L-shaped, M-shaped or T-shaped. The first grounding post 11 is a cuboid or a cylinder.

[0047] The ±45° dual-polarized antenna unit 7 includes four triangular metal patches 21; the triangular metal patches 21 are arranged in an array around the center of the ±45° dual-polarized antenna unit 7; a third grounding post 22 is provided on the triangular metal patches 21 near the center of the ±45° dual-polarized antenna unit; the second grounding post 22 is connected to the first metal plate 2.

[0048] The first metal plate 2 is etched with a plurality of cross-shaped power supply slots 12, wherein the cross-shaped slots 12 include a first I-shaped slot 13 and a second I-shaped slot 14 arranged perpendicularly to each other, and the first I-shaped slot 13 and the second I-shaped slot 14 are respectively used to excite -45° polarization and +45° polarization; the second metal plate 4 is etched with a plurality of third I-shaped slots 15; the widths at both ends of the first I-shaped slot 13, the second I-shaped slot 14 and the third I-shaped slot 15 are greater than the widths in the middle.

[0049] The second dielectric substrate 3 is provided with a -45° feed network 16; the third dielectric substrate 5 is provided with a +45° feed network 20; the ±45° dual-polarized antenna element 7, the cross-shaped feed slot 12 and the third I-shaped slot 15 are arranged correspondingly to each other; the -45° feed network 16 and the +45° feed network 20 include a power divider 17 and a metal isolation strip 18; the metal isolation strip 18 is arranged around the power divider 17; second grounding posts 19 are evenly distributed on the metal isolation strip 18.

[0050] The dielectric constant εr of the dielectric substrate is [1 10.2], and the thickness is [0.01λ, 0.3λ]. The thickness of the first metal plate 2 and the second metal plate 4 is [0.005λ, 0.1λ], where λ is the free space wavelength.

[0051] like Figures 2 to 5 As shown, the height H1 of the first dielectric substrate 1 is [0.01λ, 0.25λ], the height H2 of the second dielectric substrate 3 is [0.01λ, 0.15λ], and the height H3 of the third dielectric substrate 5 is [0.01λ, 0.15λ]; the dimensions L1 of the triangular metal patch 21 of the ±45 degree dual-polarized magnetoelectric dipole antenna element 7 are [0.01λ, 0.15λ], L2 are [0.01λ, 0.05λ], and G1 The diameter D1 of the third grounding post 22 is [0.01λ, 0.1λ]; the length L3 of the first metal strip 9 of the grounding decoupling stub 8 is [0.01λ, 0.25λ], the broadband W2 is [0.01λ, 0.1λ], the size L4 of the second metal strip 10 is [0.01λ, 0.1λ], the broadband W1 is [0.01λ, 0.25λ], and the height H4 of the first grounding post 11 is [0.05λ, 0.25λ]. [0.01λ, 0.25λ], diameter D2 is [0.01λ, 0.1λ]; the dimensions of the first I-beam gap 13, LS1 is [0.01λ, 0.2λ], LS2 is [0.01λ, 0.2λ], WS1 is [0.01λ, 0.2λ], WS2 is [0.01λ, 0.2λ]; the dimensions of the second I-beam gap 14, LS3 is [0.01λ, 0.2λ], LS4 is [0.01λ The dimensions of the third I-beam gap 15 are as follows: LS5 is [0.01λ, 0.2λ], LS6 is [0.01λ, 0.2λ], WS5 is [0.01λ, 0.2λ], and WS6 is [0.01λ, 0.2λ]. The inter-element spacing D3 is [0.2λ, 0.6λ], where λ is the free space wavelength.

[0052] In this embodiment, the preferred dimensions of each part are as follows:

[0053] The height H1 of the first dielectric substrate 1 is 0.94 mm, the height H2 of the second dielectric substrate 3 is 0.376 mm, and the height H3 of the third dielectric substrate 5 is 0.376 mm. The dimensions of the triangular metal patch 21 of the ±45-degree dual-polarized magnetoelectric dipole antenna element 7 are L1 1.2 mm, L2 0.2 mm, and G1 0.3 mm. The diameter D1 of the third grounding post 22 is 0.1 mm. The length L3 of the first metal strip 9 of the grounding decoupling stub 8 is 2.4 mm, the bandwidth W2 is 0.15 mm, the dimension L4 of the second metal strip 10 is 0.15 mm, the bandwidth W1 is 0.95 mm, and the height H4 of the first grounding post 11 is 0.47 mm. The diameter D2 is 0.1mm; the dimensions of the first H-beam gap 13 are LS1 0.1mm, LS2 0.66mm, WS1 0.95mm, and WS2 0.6mm; the dimensions of the second H-beam gap 14 are LS3 0.14mm, LS4 0.5mm, WS3 0.9mm, and WS4 0.46mm; the dimensions of the third H-beam gap 15 are LS5 0.1mm, LS6 0.62mm, WS5 1.33mm, and WS6 0.47mm; the inter-unit spacing D3 is 4.5mm; the dielectric constant εr of the dielectric substrate is 5.9; and the thickness of the first metal plate 2 and the second metal plate 4 is 0.008mm.

[0054] like Figure 8 and Figure 9 As shown, this high-isolation broadband ±45° dual-polarized millimeter-wave subarray has an operating bandwidth covering 24.25-29.5 GHz, an in-band reflection coefficient below -15 dB, and in-band isolation greater than 22 dB. Compared to an unloaded decoupling grounding stub, port isolation is improved by 6 dB; the decoupling grounding stub used is also suitable for broadband applications, effectively improving the isolation of the ±45° dual-polarized subarray.

[0055] like Figure 10 As shown, after adding the decoupling grounding stub, the antenna efficiency of this high-isolation broadband ±45° dual-polarized millimeter-wave subarray is improved at all frequency points within the 24.25-29.5GHz band. For antenna efficiency when only -45° polarization is excited, the efficiency increases from 76%–82% to 81%–84% after adding the decoupling grounding stub; for antenna efficiency when only +45° polarization is excited, the efficiency increases from 73%–81% to 80%–82.7%. This embodiment can be widely applied to decoupling arrays of different numbers and polarizations; it can effectively improve the scanning performance of ±45° dual-polarized phased arrays and suppress cross-polarization during large-angle scanning; it can effectively improve the scanning performance of phased arrays, making gain fluctuations more stable during scanning.

[0056] Example 2

[0057] like Figure 11 and Figure 22 As shown, a phased array antenna includes four broadband ±45° dual-polarized millimeter-wave subarrays with high isolation as described in Embodiment 1, and the broadband ±45° dual-polarized millimeter-wave subarrays are arranged in an array along the X-axis with the same array spacing D4. This embodiment has a simple structure, is easy to manufacture, has a relatively low cost, and can achieve mass production.

[0058] The scanning range of the phased array is affected by the array spacing D4; the smaller the array spacing, the larger the scanning range. The array spacing D4 can be [0.2λ, 0.6λ], where λ is the free space wavelength. In Embodiment 2, the preferred size of D4 is 4.5 mm.

[0059] like Figure 13 and Figure 14 As shown, the phased array has a working bandwidth of 24.25-29.5 GHz, an in-band reflection coefficient of less than -15 dB, and an isolation of more than 20 dB between the ±45° polarizations of the four subarrays within the band.

[0060] like Figure 15 As shown, after adding the decoupling grounding stub, the cross-polarization ratio of the phased array increased from 11dB to 18dB when scanning to the maximum angle. This demonstrates that the decoupling grounding stub suppresses cross-polarization in the ±45° dual-polarization phased array during scanning.

[0061] like Figure 16 As shown, the phased array scanning performance was improved after adding a decoupling ground stub. At 29.5 GHz, scanning to -56°, the gain ripple was improved from 3.6 dB to 2.8 dB.

[0062] like Figure 17 , Figure 18 , Figure 19 and Figure 23 As shown, the phased array's -45° polarization exhibits excellent scanning performance. At 24.25 GHz, it can scan down to -59° with a gain fluctuation of approximately 3 dB; at 27 GHz, it can scan down to -57° with a gain fluctuation of approximately 2.9 dB; at 29.5 GHz, it can scan down to -56° with a gain fluctuation of approximately 2.8 dB; and when scanning to the maximum angle, the active S-parameter is below -8.5 dB.

[0063] like Figure 20 , Figure 21 , Figure 22 and Figure 24As shown, the +45° polarization of the phased array exhibits good scanning performance. At 24.25 GHz, it can scan down to -58° with a gain fluctuation of approximately 3 dB; at 27 GHz, it can scan down to -57° with a gain fluctuation of approximately 2.8 dB; at 29.5 GHz, it can scan down to -53° with a gain fluctuation of approximately 3 dB; and when scanning to the maximum angle, the active S-parameter is below -8.9 dB.

[0064] In phased array antennas, cross-polarization during large-angle scanning is suppressed by loading decoupling ground stubs, which also effectively improves the scanning performance of the phased array antenna and makes the gain fluctuation more stable during scanning.

[0065] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A broadband ±45° dual-polarized millimeter-wave subarray, characterized in that, It includes a first dielectric substrate, a first metal plate, a second dielectric substrate, a second metal plate, a third dielectric substrate, and a third metal ground plate that are stacked and arranged in sequence. The first dielectric substrate is arranged in an array of several ±45° dual-polarized antenna elements and several decoupling grounding branches. The first metal plate is etched with several cross-shaped feed slots. The second dielectric substrate is provided with a -45° feed network and the second metal plate is etched with several third I-shaped slots. The third dielectric substrate is provided with a +45° feed network. The ±45° dual-polarized antenna elements, cross-shaped feed slots and third I-shaped slots are arranged in a corresponding manner to each other. The decoupling grounding stub is set between every two ±45° dual-polarized antenna elements. The decoupling grounding stub acts to change the coupling amplitude and phase of the ±45° polarization between the ±45° dual-polarized antenna elements, so that the ±45° polarization coupling cancels each other out. The decoupling grounding branch includes two first metal strips placed side by side and two second metal strips placed side by side; the second metal strips are disposed between the two first metal strips, and the first metal strips and the second metal strips are arranged perpendicular to each other; a first grounding post is provided at the center of the first metal strip; the first grounding post is embedded in the first dielectric substrate; the first grounding post is connected to the first metal plate; The ±45° dual-polarized antenna unit includes four triangular metal patches; the triangular metal patches are arranged in an array around the center of the ±45° dual-polarized antenna unit; a third grounding post is provided on each triangular metal patch near the center of the ±45° dual-polarized antenna unit; the third grounding post is connected to the first metal plate.

2. The broadband ±45° dual-polarized millimeter-wave subarray according to claim 1, characterized in that, The cross-shaped power supply gap includes a first I-beam gap and a second I-beam gap arranged perpendicularly to each other. The first I-beam gap and the second I-beam gap are respectively used to excite -45° polarization and +45° polarization.

3. The broadband ±45° dual-polarized millimeter-wave subarray according to claim 1, characterized in that, The -45° and +45° power supply networks include a power divider and a metal isolation strip; the metal isolation strip is arranged around the power divider; and second grounding posts are evenly distributed on the metal isolation strip.

4. The broadband ±45° dual-polarized millimeter-wave subarray according to claim 1, characterized in that, The first dielectric substrate, the second dielectric substrate, and the third dielectric substrate are made of low-temperature co-fired ceramic substrates or PCB dielectric substrates.

5. A phased array antenna, characterized in that, It includes multiple broadband ±45° dual-polarized millimeter-wave subarrays arranged in an array as described in any one of claims 1 to 4; it suppresses cross-polarization when scanning to the maximum angle by loading decoupling ground stubs, while making gain fluctuations more stable.

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